You remind me of a famous line from the movie ‘让子弹飞’: “你带着老婆，坐着火车，吃着火锅还唱着歌，突然就让麻匪给劫了！”
Here, verb+着 is similar to ‘doing’ in English, indicating the progressive aspect. So the line mentioned above means, ‘you were doing blablabla when you were robbed.’

Well, back to your question, I'm afraid all your sentences sound weird or unfinished to me. I would say, the most concise way should be 我们走路去学校.
You can also say 我们走着去学校. This is more common in spoken language and means the same as 我们走路去学校, but you need more context. e.g.:
– 你们住的地方离学校远不远？你们怎么去学校？(Do you live very far away from the school? How do you go to school?)
- 不远，我们走着去（学校）。(Not at all. We walk to school.)
But here 走着 doesn't mean ‘walking’...perhaps 走着去 emphasises the action 去, and 走着 is answering 'how'.

You remind me of a famous line from the movie ‘让子弹飞’: “你带着老婆，坐着火车，吃着火锅还唱着歌，突然就让麻匪给劫了！”
Here, verb+着 is similar to ‘doing’ in English, indicating the progressive aspect. So the line mentioned above means, ‘you were doing blablabla when you were robbed.’

Well, back to your question, I'm afraid all your sentences sound weird or unfinished to me. I would say, the most concise way should be 我们走路去学校.
You can also say 我们走着去学校. This is more common in spoken language and means the same as 我们走路去学校, but you need more context. e.g.:
– 你们住的地方离学校远不远？你们怎么去学校？(Do you live very far away from the school? How do you go to school?)
- 不远，我们走着去（学校）。(Not at all. We walk to school.)
But here 走着 doesn't mean ‘walking’...perhaps 走着去 emphasises the action 去, and 走着 is answering 'how'.